the comparative frequency with which gall stones occur and the extreme rarity of primary cancer of the gall bladder. With regard to the former, it has been estimated by Kehr and others tthat gall stones are present in about Io per cent. of all adults, as determined by po8t-mortem examination. With regard to the latter, the rarity of primary cancer of the gall bladder is so great that of 7,297 cancer patients under treatment in large London hospitals I found only I I had primary cancer of the

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... l bladder; and of ii, I3I cancer patients in the Vienna hospitals Gurlt found only 5 instances of primary cancer of the gall bladder. I submit that these figures only admit of one interpretation, namely, that cancer of the gall bladder is not caused by the gall stones so often found in association with it. It seems to me that facts of this kind ought not" to be ignored.-I remain, etc., J Clifton, Bristol, Dec. 5th. W. ROGER WILLIAMS.